Contiki
( http://www.contiki-os.org/ ) is an open source operatingsystem for networked, memory-constrained systems with a
particular focus on low-power wireless
Internet of Things devices.
Examples of where Contiki is used include street lighting systems, sound
monitoring for smart cities,
radiation monitoring systems, and alarm systems.See Wikipedia:

If you are STM registered customer here there is the last release of the CONTIKI porting for STM32W (contiki-26).
If you are STM registered customer here there is the: Contiki Demo Application Quick Start Guide v.0.1
After dowload the SW and the DOC please send me an emailwith your STM customer registration and I give you the passwords for open it.